Date: Sat, 26 Mar 2022 16:12:27 +0000 From: bugzilla-noreply@freebsd.org To: freebsd-arm@FreeBSD.org Subject: [Bug 262836] [arm64] cacheline flush instruction (dc cvau) causes SIGSEGV from userland Message-ID: <bug-262836-7@https.bugs.freebsd.org/bugzilla/>
next in thread | raw e-mail | index | archive | help
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=3D262836 Bug ID: 262836 Summary: [arm64] cacheline flush instruction (dc cvau) causes SIGSEGV from userland Product: Base System Version: CURRENT Hardware: arm64 OS: Any Status: New Severity: Affects Some People Priority: --- Component: arm Assignee: freebsd-arm@FreeBSD.org Reporter: dch@freebsd.org Created attachment 232744 --> https://bugs.freebsd.org/bugzilla/attachment.cgi?id=3D232744&action= =3Dedit https://git.sr.ht/~dch/src/commit/ae9221b85d18b6816276b8401734548f03b89013.= patch building OTP-25-RC2 from source yields a segfault during build. After some build finagling, we can narrow this down to `dc cvau` failing: ``` sudo lldb ./bin/aarch64-unknown-freebsd14.0/beam.debug.jit (lldb) target create "./bin/aarch64-unknown-freebsd14.0/beam.debug.jit" Current executable set to '/tmp/otp/bin/aarch64-unknown-freebsd14.0/beam.debug.jit' (aarch64). (lldb) run Process 40356 launched: '/tmp/otp/bin/aarch64-unknown-freebsd14.0/beam.debug.jit' (aarch64) Process 40356 stopped * thread #1, name =3D 'beam.debug.jit', stop reason =3D signal SIGSEGV: add= ress access protected (fault address: 0xdee00000) frame #0: 0x0000000000769f54 beam.debug.jit`__clear_cache(start=3D0x00000000dee00000, end=3D0x00000000de= e0294c) at clear_cache.c:119:7 116 const size_t dcache_line_size =3D 4 << ((ctr_el0 >> 16) & 15); 117 for (addr =3D xstart & ~(dcache_line_size - 1); addr < xend; 118 addr +=3D dcache_line_size) -> 119 __asm __volatile("dc cvau, %0" ::"r"(addr)); 120 } 121 __asm __volatile("dsb ish"); 122 (lldb) bt * thread #1, name =3D 'beam.debug.jit', stop reason =3D signal SIGSEGV: add= ress access protected (fault address: 0xdee00000) * frame #0: 0x0000000000769f54 beam.debug.jit`__clear_cache(start=3D0x00000000dee00000, end=3D0x00000000de= e0294c) at clear_cache.c:119:7 frame #1: 0x00000000003feb60 beam.debug.jit`BeamAssembler::_codegen(this=3D0x00000000d4b0e000, allocator=3D0x000000008b16c018, executable_ptr=3D<unavailable>, writable_ptr=3D<unavailable>) at beam_jit_common.cpp:128:5 frame #2: 0x00000000003ea4e8 beam.debug.jit`BeamGlobalAssembler::BeamGlobalAssembler(this=3D0x00000000d4= b0e000, allocator=3D0x000000008b16c018) at beam_asm_global.cpp:71:9 frame #3: 0x00000000004034dc beam.debug.jit`::beamasm_init() at beam_jit_main.cpp:256:15 frame #4: 0x000000000049c908 beam.debug.jit`erl_init(ncpu=3D32, proc_tab_sz=3D262144, legacy_proc_tab=3D0, port_tab_sz=3D65536, port_tab_sz_ignore_files=3D0, legacy_port_tab=3D0, sys_proc_outst_req_lim= =3D64, time_correction=3D1, time_warp_mode=3DERTS_NO_TIME_WARP_MODE, node_tab_delete_delay=3D60, db_spin_count=3DERTS_DB_SPNCNT_NORMAL) at erl_init.c:355:5 frame #5: 0x000000000049b0a8 beam.debug.jit`erl_start(argc=3D1, argv=3D0x000000008144b690) at erl_init.c:2424:5 frame #6: 0x00000000003c0828 beam.debug.jit`main(argc=3D1, argv=3D0x000000008144b690) at erl_main.c:30:5 frame #7: 0x00000000003c063c beam.debug.jit`__start(argc=3D1, argv=3D0x000000008144b690, env=3D0x000000008144b6a0, cleanup=3D<unavailable= >) at crt1_c.c:72:7 frame #8: 0x0000236d2a2f60d8 ld-elf.so.1`.rtld_start at rtld_start.S:41 (lldb) x/8i $pc-16 0x769f44: 0xcb0903ea neg x10, x9 0x769f48: 0x8a00014a and x10, x10, x0 0x769f4c: 0xeb01015f cmp x10, x1 0x769f50: 0x540000a2 b.hs 0x769f64 ; <+76> at clear_cache.c:121:3 -> 0x769f54: 0xd50b7b2a dc cvau, x10 0x769f58: 0x8b09014a add x10, x10, x9 0x769f5c: 0xeb01015f cmp x10, x1 0x769f60: 0x54ffffa3 b.lo 0x769f54 ; <+60> at clear_cache.c:119:7 (lldb) x/8i start 0xdee00000: 0xaa1f03e2 mov x2, xzr 0xdee00004: 0xaa1903e3 mov x3, x25 0xdee00008: 0xaa1a03e4 mov x4, x26 0xdee0000c: 0xaa0403e8 mov x8, x4 0xdee00010: 0x91020269 add x9, x19, #0x80 ; =3D0x80 0xdee00014: 0xf100ed1f cmp x8, #0x3b ; =3D0x3b 0xdee00018: 0x54000240 b.eq 0xdee00060 0xdee0001c: 0x37080148 tbnz w8, #0x1, 0xdee00044 (lldb) x/8i end 0xdee0294c: 0x00000000 udf #0x0 0xdee02950: 0x00000000 udf #0x0 0xdee02954: 0x00000000 udf #0x0 0xdee02958: 0x00000000 udf #0x0 0xdee0295c: 0x00000000 udf #0x0 0xdee02960: 0x00000000 udf #0x0 0xdee02964: 0x00000000 udf #0x0 0xdee02968: 0x00000000 udf #0x0 (lldb) x/8i $x0 0xdee00000: 0xaa1f03e2 mov x2, xzr 0xdee00004: 0xaa1903e3 mov x3, x25 0xdee00008: 0xaa1a03e4 mov x4, x26 0xdee0000c: 0xaa0403e8 mov x8, x4 0xdee00010: 0x91020269 add x9, x19, #0x80 ; =3D0x80 0xdee00014: 0xf100ed1f cmp x8, #0x3b ; =3D0x3b 0xdee00018: 0x54000240 b.eq 0xdee00060 0xdee0001c: 0x37080148 tbnz w8, #0x1, 0xdee00044 (lldb) x/8i $x1 0xdee0294c: 0x00000000 udf #0x0 0xdee02950: 0x00000000 udf #0x0 0xdee02954: 0x00000000 udf #0x0 0xdee02958: 0x00000000 udf #0x0 0xdee0295c: 0x00000000 udf #0x0 0xdee02960: 0x00000000 udf #0x0 0xdee02964: 0x00000000 udf #0x0 0xdee02968: 0x00000000 udf #0x0 (lldb) x/8i $x9 error: memory read failed for 0x0 (lldb) x/8i $x10 0xdee00000: 0xaa1f03e2 mov x2, xzr 0xdee00004: 0xaa1903e3 mov x3, x25 0xdee00008: 0xaa1a03e4 mov x4, x26 0xdee0000c: 0xaa0403e8 mov x8, x4 0xdee00010: 0x91020269 add x9, x19, #0x80 ; =3D0x80 0xdee00014: 0xf100ed1f cmp x8, #0x3b ; =3D0x3b 0xdee00018: 0x54000240 b.eq 0xdee00060 0xdee0001c: 0x37080148 tbnz w8, #0x1, 0xdee00044 (lldb) ``` andrew@ produced a small patch which seems to be sufficient (attached). It would be great to have a fix for this included in 13.1-RELEASE arm64 if possible. --=20 You are receiving this mail because: You are the assignee for the bug.=
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?bug-262836-7>